Damper for an air duct

ABSTRACT

A damper device for use with an air duct provides a paddle positioned within the duct and an axle extending distally from, and in a common plane with, the paddle through the duct wall, to a position for manual adjustment of the paddle within the duct. A bushing is tightened against the wall of the duct by a threaded knob and frictionally holds the axle in place using a combination of axially oriented fingers and O-rings. A handle is engaged with the end of the axle, enabling manual adjustment of the angular position of the paddle from outside the duct. The handle is in fixed alignment with the orientation of the paddle&#39;s peripheral edge, allowing for identification of the approximate angular position of the paddle from outside the duct, even when the duct is covered with a layer of insulation.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC

Not applicable.

REFERENCE TO A “MICROFICHE APPENDIX”

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Present Disclosure

This disclosure relates generally to generally to duct dampers, and moreparticularly to an air duct damper providing cantilevered construction,ease of installation, and features for improving the ability to locatethe damper adjustment control.

2. Description of Related Art including information disclosed under 37CFR 1.97 and 1.98

Breckenridge, U.S. Pat. No. 160,386 discloses a spindle of a damperplate, constructed with a notch, combined with a spring arranged toenter and bear against the edge of the perforation in the pipe, as wellas non-heat-conducting pads arranged in recesses in the handle in eachside of the center.

Mears, U.S. Pat. No. 184,255 discloses a rosette-spring, of platematerial, constructed as described, in combination with a shaft, disk,and tubular handle, operating to hold a damper in adjusted position inthe pipe by frictional contact.

Barler, U.S. Pat. No. 348,947 discloses a damper for stove pipes andhot-air flues comprising the combination of a disk, having anenlargement, journal, angular shank, and screw-seat, a tubular handle,having an enlarged end, and a pipe.

Packham, U.S. Pat. No. 485,053 discloses a damper consisting of adamper-disk having a slideway produced centrally therein, a shank,having at one end a stud forming a journal for one end thereof andrecessed, adjacent to the stud, said recess forming an integraloverhanging lug or hook adapted to overlie the peripheral edge of thedamper-disk received in the recess, the opposite end of the shank havinga suitable handle and formed with a shoulder, and a coiled spring on thehandle end of the shank, normally tending to press the overhanging lugat the recessed end of the shank into engagement with the peripheraledge of the disk, thereby serving to maintain the engagement of such lugirrespective of any warping of the disk.

Fauth, U.S. Pat. No. 784,997 discloses a damper consisting of adamper-lever having a screw-thread, a damper connected with the leverand fitted in the duct in connection with a locking-nut mounted on thethreaded portion of the lever and adapted to be turned thereon againstthe outer surface of the duct, or a disk or plate thereon, whereby tolock the damper securely in place.

Leo, U.S. Pat. No. 971,285 discloses an improvement in air pipe dampers,the combination with a pipe section having a pair of diametricallyopposite openings, and a combined reinforcing block, and bearing in eachof said openings, said blocks projecting on the inside of the pipe; ofthe damper, a pair of oppositely disposed clip members secured to thedamper, each of which has a trunnion, one of said trunnions engaging thebearing at one side, the other trunnion being extended through the otherbearing or block, said trunnions each having a shoulder for abutting thebearing at their respective sides, the extended trunnion having itsouter end apertured, a flat spring plate secured at one end to the pipeand having an elongated slot through which the long trunnion passes, alever handle comprising a forked cam head eccentrically and pivotallymounted on the outer end of the extended journal, said cam head engagingsaid spring plate adjacent to its slot, said spring plate being heldbetween said lever and the adjacent part of the pipe section.

Fletcher, U.S. Pat. No. 1,875,581 discloses a combination of a flue anddamper oscillatable therein, between open and closed positions withoperating mechanism therefor comprising in combination, a housing havinga part rotatable therein which is spring pressed in one direction, atrunnion on said damper, a wall plate, an operating member having a hubprovided with a circumferential recess and a longitudinal groove, aretaining plate having an opening in which said hub is rotatable and aninwardly extending lip in said recess to hold said operating member andretaining plate against separation except when said groove and lip arein alignment, connections between said member, the rotatable part insaid housing and a trunnion on said damper.

Rosenberg, U.S. Pat. No. 1,919,863 discloses a damper plate and damperrod adapted to outstand through the wall of a flue, of a sleeveslidingly and non-rotatingly engaging the rod, a nut threaded onto therod beyond the sleeve for effecting a relatively clamping action betweenthe sleeve and damper plate, and an annulus surrounding the rod andproviding a bearing therefor, directly engaging the rod, the annulusalso providing a seat for the end of the sleeve.

Sladky, U.S. Pat. No. 2,412,918 discloses a butterfly valve mechanismcomprising a valve body having an opening through which fluid may beconducted, a shaft extending across said opening, a valve disc affixedto said shaft and moveable therewith between closed and open positions,a flat ring of generally washer form surrounding said disc and mountedfor swinging movement about the shaft axis, and means for affixing saidring selectively either to the valve body or to the shaft for movementwith said disc.

Guildford, U.S. Pat. No. 2,702,504 discloses an air duct control meansthat provides a damper regulating means which is ordinarily inaccessibleto tampering by persons who are not authorized or qualified to makechanges in damper adjustments.

Powers, U.S. Pat. No. 2,765,726 discloses a means for re-circulatingheating air. The invention provides for using the draft of the incominghot air to cause a continued re-circulation of the air in the roomthereby preventing the stratification so common in which the lower areasare cold and the ceiling areas are hot. This stratification produces theeffect of coolness or chilliness to be felt by the occupant of the room.

Kennedy, U.S. Pat. No. 3,070,346 discloses a flow control damper whichis simpler and less costly in construction. This invention is adaptableto a wider range of duct sizes without alteration and is adjustable froman operating point within the duct, and is quieter in operation and moreeffective in sealing the duct fully closed.

Russell, U.S. Pat. No. 4,646,715 discloses an extension apparatus for adamper assembly having an extension member for effectively extending thedamper assembly control shaft and a securing member for securing theextension member onto the control shaft.

Inglis, U.S. Pat. No. 4,688,472 discloses a spoiler that is located onthe damper blade of a damper assembly such that it serves to divert theflow from the hinge area to avoid air separation. Further, the spoilerdoes not define the most restricted portion of the flow path and therebyhas a minimal effect on the flow resistance.

Shepherd et al., U.S. Pat. No. 4,691,689 discloses an adjustable damperhaving a tubular duct section defining first and second diametricallyopposed openings and first and second sets of detents formed radiallyfrom the material of the duct about the respective openings to define aplurality of damper settings.

Myers, U.S. Pat. No. 4,715,581 discloses a damper to be pivotallymounted and eventually clamped in a cylindrical air duct which includesa circular damper blade, a first pivot pin extending integrally radiallyoutwardly from the blade, a damper clip mounted on the opposite side ofthe blade to have a slideably mounted second pivot pin extendingradially outwardly from the blade on the same diameter as the first pin.The blade is provided with a pair of parallel, spaced-apart, andupstanding positioning beads situated to positively position the damperclip and the axis of the second pivot pin. A pair of parallel,spaced-apart elongate, upstanding stiffening beads are spaced from andparallel to the diametrical axes of the positioning pins.

Bernal, U.S. Pat. No. 5,921,277 discloses a damper device for use withan air duct which provides a paddle positioned within the air duct andan axle extending to one side of the paddle, through the duct wall andinsulation to a position for manual adjustment of the position of thepaddle within the duct. A bushing holds the axle in place, the bushingbeing tightened against the wall of the duct by a hand nut. The hand nutprovides a brightly colored flag that is extendable when the damperdevice is in place. An O-ring is used to cause a frictional relationshipbetween the paddle axle and the bushing so that the paddle is fixed intoplace once adjusted. A contour step on the bushing face allowsengagement between the paddle and the bushing so as to hold the bushingfrom rotating while the hand nut is threaded into place on the bushing.

The related art described above discloses dampers. However, the priorart fails to disclose an air damper that is supported from one side ofthe duct only, is easily installed and operated without tools, and ismade entirely of relatively inexpensive molded plastic parts. Thepresent disclosure distinguishes over the prior art providing heretoforeunknown advantages as described in the following summary.

BRIEF SUMMARY OF THE INVENTION

This disclosure teaches certain benefits in construction and use whichgive rise to the objectives described below.

The prior art teaches damper devices providing a disk-shaped controlsurface or paddle, supported on opposing sides by a threaded stud whichpenetrates an air duct and is held in place by wing nuts or similarhardware. A handle is mounted on each of the threaded studs in order tofacilitate angular positioning of the paddle, the handle alsoindicating, by virtue of its orientation, the orientation, as well, ofthe paddle within the duct. It is important to notice that, in order tomount the prior art damper device in this prior art scheme, it isnecessary to have physical access to both sides of the duct, somethingnot always available and highly dependent upon details of theconstruction site. Further, it is clear that the 4 to 6 inches ofinsulating material that is normally placed around such ducts completelycovers the handle so that it normally is difficult for air conditioningservice personnel to find the locations of the handles in order toadjust air volume flows within such duct systems. The prior art devicesalso require a complex construction with springs loading the studs,enabling the studs to be retracted during installation of the paddle.This approach is, of course, expensive in both parts production andrequired labor.

The applicant's prior patent solved many of these problems by teaching adamper device that is supported from only one side of the air duct, andhas a simple installation without using any tools. In addition, thedamper device may have flag storage and displaying capabilities for useby workmen.

The present invention significantly improves on applicant's prior patentby teaching a damper device for use with an air duct which provides apaddle positioned within the air duct and an axle extending to one sideof the paddle, through the duct wall, to a position for manualadjustment of the paddle within the duct. A bushing is tightened againstthe wall of the duct by a threaded knob and frictionally holds the axlein place using rubber O-rings so that the paddle is fixed into placeonce adjusted. A bar handle is engaged with the end of the axle,enabling manual rotation of the axle, and adjustment of the angularposition of the paddle, from outside the air duct. The handle is infixed alignment with the orientation of the paddle's peripheral edge,and the knob provides angle-related marker means. Thus, the handle andthe marker means cooperate, as the handle is rotated, to identify theapproximate angular position of the paddle from outside the air duct,even when the duct is covered with a layer of insulation. No tools areneeded to install or adjust the paddle, other than a drill to make ahole in the side of the air duct. In addition, the device is madeentirely of molded plastic parts. Therefore, the present inventionimproves on the prior art by teaching a device that is relatively lessexpensive in both parts production and required labor.

A primary objective inherent in the above described apparatus and methodof use is to provide advantages not taught by the prior art.

Another objective is to provide an air duct damper that has advantagesin installation and use not taught by the prior art.

A further objective is to provide such an air duct damper that isconvenient to install from one side of the duct rather than requiringaccess to both sides of the duct.

A further objective is to provide such an air duct damper that isadjustable without removing or disturbing the duct insulation.

A further objective is to provide such an air duct damper that is ableto be seen in dim light and not easily covered up by duct insulation.

A further objective is to provide such an air duct damper that can bemounted in an air duct and tightened in place, without using any tools.

A further objective is to provide such an air duct damper that is madeentirely out of molded plastic parts.

A further objective is to provide such an air duct damper that has a barhandle that enables for manual adjustment of the angular position of thepaddle from outside the air duct without using any tools.

A still further objective is to provide such an air duct damper wherethe same bar handle allows for the identification of the approximateangular position of the paddle from outside the air duct, even when theduct is covered with a layer of insulation.

Other features and advantages of the present invention will becomeapparent from the following more detailed description, taken inconjunction with the accompanying drawings, which illustrate, by way ofexample, the principles of the presently described apparatus and methodof its use.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Illustrated in the accompanying drawing(s) is at least one of the bestmode embodiments of the present invention In such drawing(s):

FIG. 1 is a perspective exploded view of the present invention showingan air duct with a proximal portion removed so as to show interiordetails;

FIG. 2 is a perspective view of the present invention assembled outsideof an air duct for illustrative purposes;

FIG. 3 is a perspective view of the bushing portion of the presentinvention;

FIG. 4 is a perspective view of the handle portion of the presentinvention;

FIG. 5 is a cross-sectional view of the knob portion of the presentinvention; and

FIG. 6 is a cross-sectional view of the bushing portion of the presentinvention.

DETAILED DESCRIPTION OF THE INVENTION

The above described drawing figures illustrate the described apparatusand its method of use in at least one of its preferred, best modeembodiment, which is further defined in detail in the followingdescription. Those having ordinary skill in the art may be able to makealterations and modifications to what is described herein withoutdeparting from its spirit and scope. Therefore, it must be understoodthat what is illustrated is set forth only for the purposes of exampleand that it should not be taken as a limitation in the scope of thepresent apparatus and method of use.

Described now in detail is a damper device for use with an air duct 5and other types of fluid flow conduits. The damper device is made up ofa damper paddle 30, a paddle axle 20, a handle 10, a knob 40, and atubular bushing 50 as clearly shown in FIG. 1. Each one of thecomponents is a molded plastic part; however, other materials may besubstituted in this application. Paddle 30 and axle 20 are molded as aunitary part but may be connected in other ways. Axle 20 extendsdistally from, and in a common plane with paddle 30.

As shown in FIGS. 3 and 6, bushing 50 provides a bushing head 54 at aproximal end and a bushing body 58 extending distally from bushing head54. Bushing body 58 has external threads 58A, which may be a machinethread and may cover all or part of bushing body 58. Bushing body 58 iscoaxially engaged with axle 20. At the distal end of bushing 50, areaxially oriented, separate bushing fingers 52 which each terminatedistally with a inwardly extending tip 52A. As shown in FIG. 1, axle 20has a portion 22 at a reduced diameter which receives tips 52A therebyremovably securing the bushing 50 to axle 20 at a location dictated byportion 22. In addition, axle 20 provides two flexible rubber O-rings 26which are of a slightly larger diameter than axle 20 so that there is africtional relationship between axle 20 and bushing 50 so that axle 20,with paddle 30 requires a selected minimum force to rotate. In thepreferred application it is impossible for an air stream alone, to forcepaddle 30 into a new rotational position once manually set.

Knob 40 is threaded onto bushing body 58 and therefore axially movablealong threads 58A. Bushing head 54 provides a head surface 56 directedtoward paddle 30. Head surface 56 contains radial steps 56A, each one ofwhich is a step in a contour of head surface 56, providing a means forengaging a peripheral edge 32 of paddle 30. With the peripheral edge 32manually placed into contact with the radial steps 56A, bushing 50 isprevented from turning, thus allowing knob 40 to be tightened ontobushing 50 without the latter turning. As shown in FIG. 6, bushing 50provides a tapered surface 58B between bushing head 54 and threads 58Afor locking knob 40 on bushing 50. In addition, as shown in FIG. 5, knob40 further provides a circular recess 46 which flexes outwardly as knob40 is engaged with tapered surface 58B, thereby producing radialcompressive forces for securing knob 40 in place. Thus, once knob 40 isthreadably engaged with bushing 50, the two parts lock together androtate about axle 20 as a single unit. After tightening, paddle 30 ismoved laterally out of contact with head surface 56 and its radial steps56A so that paddle 30 is free to rotate within bushing 50.

Axle 20 extends distally beyond bushing body 58, terminating with aD-shaped axle end 24. Handle 10, shown in detail in FIG. 4, has acorrespondingly-sized D-shaped handle hole 12 that fits the D-shapedaxle end 24. Axle end 24 is also axially slotted so that it can becompressed, enabling it to enter handle hole 12, thereby snapping handle10 into place on axle 20. Once engaged, the D shape enables handle 10for rotation and adjustment of the position of paddle 30. Handle 10 isin fixed alignment with the orientation of the peripheral edge 32 ofpaddle 30, as shown in FIG. 2. Thus, regardless of the angular positionof paddle 30, handle 10 will always reflect that angular position. Inaddition, knob 40 preferably provides eight angularly spaced apartradial markers 44, as shown in FIG. 1, with each marker 44 being spaced45° apart and radially positioned around axle 20. Handle 10 alsocontains an axial slot 14 extending linearly down one side. This slot 14may be used to hold a flag (not shown), such as a ribbon or othersimilar material, allowing for identification of the approximate angularposition of paddle 30, as well as the location of the present inventionitself when it is positioned within the air duct 5, as discussed below.

When in use, paddle 30 is positioned within the air duct 5, with axle 20extending through a mounting hole 5H located on a wall 5W of the airduct 5, as shown in the exploded view of FIG. 1. Bushing head 54 ispositioned against an inner surface 5A of the air duct 5, and knob 40 isthen threaded onto bushing body 58 until an end surface 42 of knob 40,best seen in FIGS. 2 and 5, engages with an outer surface 5B of the airduct 5. Thus, wall 5W is tightly sandwiched between head 54 and endsurface 42, creating an airtight seal. Handle 10 and the markers 44cooperate, as handle 10 is rotated, to identify the approximate angularposition of paddle 30 from outside the air duct 5, even when the duct 5is covered with a layer of insulation. Slot 14 can also operate toidentify the approximate angular position of paddle 30 from outside theair duct 5, as discussed above.

The enablements described in detail above are considered novel over theprior art of record and are considered critical to the operation of atleast one aspect of the apparatus and its method of use and to theachievement of the above described objectives. The words used in thisspecification to describe the instant embodiments are to be understoodnot only in the sense of their commonly defined meanings, but to includeby special definition in this specification: structure, material, oracts beyond the scope of the commonly defined meanings. Thus if anelement can be understood in the context of this specification asincluding more than one meaning, then its use must be understood asbeing generic to all possible meanings supported by the specificationand by the word or words describing the element.

The definitions of the words or drawing elements described herein aremeant to include not only the combination of elements which areliterally set forth, but all equivalent structure, material or acts forperforming substantially the same function in substantially the same wayto obtain substantially the same result. In this sense it is thereforecontemplated that an equivalent substitution of two or more elements maybe made for any one of the elements described and its variousembodiments or that a single element may be substituted for two or moreelements in a claim.

Changes from the claimed subject matter as viewed by a person withordinary skill in the art, now known or later devised, are expresslycontemplated as being equivalents within the scope intended and itsvarious embodiments. Therefore, obvious substitutions now or later knownto one with ordinary skill in the art are defined to be within the scopeof the defined elements. This disclosure is thus meant to be understoodto include what is specifically illustrated and described above, what isconceptually equivalent, what can be obviously substituted, and alsowhat incorporates the essential ideas.

The scope of this description is to be interpreted only in conjunctionwith the appended claims and it is made clear, here, that each namedinventor believes that the claimed subject matter is what is intended tobe patented.

1. A damper apparatus for controlling air flow within an air duct, theapparatus comprising: an axle engaging a paddle, the axle extendingdistally from the paddle in a common plane with the paddle, a distalportion of the axle providing an axially oriented slot and a D-shapedcross section; a tubular bushing frictionally engaged with the axle, thebushing providing a proximal head and distal external threads, thebushing frictionally engaged with axle; a knob threadedly engaged on thebushing; and a handle providing a D-shaped handle hole engaged with theD-shaped cross section distal portion of the axle.
 2. The apparatus ofclaim 1 wherein the distal end of the bushing provides a plurality ofaxially oriented, separate fingers, each of the fingers terminatingdistally at an inwardly extending tip.
 3. The apparatus of claim 2wherein the axle provides a distal reduced diameter portion, the fingersengaged therewith.
 4. The apparatus of claim 1 wherein the axle providesat least one flexible rubber O-ring, the at least one O-ring of adiameter as to create rotational resistance between the axle and thebushing.
 5. The apparatus of claim 1 wherein the bushing provides atapered surface between the head and the external threads, the knobengaging the tapered surface for locking the knob on the bushing.
 6. Theapparatus of claim 1 wherein the proximal head of the bushing providesradial steps engagable with a peripheral edge of the paddle.
 7. Theapparatus of claim 1 wherein the handle provides an axial slot.
 8. Theapparatus of claim 1 wherein the knob provides a plurality of angularlyspaced apart radial markers, the handle and the markers cooperating toidentify the approximate angular position of the paddle.
 9. Theapparatus of claim 5 wherein the knob provides a circular recess whereinwith the knob engaged with the tapered surface of the bushing, an innerwall of the circular recess flexes outwardly, thereby producing radialcompressive forces for securing the knob in place.
 10. A combinationdamper apparatus for controlling air flow, the apparatus comprising: anair duct; an axle engaging a paddle, the axle extending distally fromthe paddle in a common plane with the paddle, a distal portion of theaxle providing an axially oriented slot and a D-shaped cross section; atubular bushing frictionally engaged with the axle, the bushingproviding a proximal head and distal external threads, the bushingfrictionally engaged with axle; a knob threadedly engaged on thebushing; a handle providing a D-shaped handle hole engaged with theD-shaped cross section distal portion of the axle; and the air ductproviding a damper mounting hole in a side wall of the air duct, thepaddle positioned within the air duct, the axle extending through themounting hole, the bushing head positioned against an inner surface ofthe air duct, and the knob engaged with an outer surface of the air ductfor securing the paddle within the air duct.
 11. The apparatus of claim10 wherein the distal end of the bushing provides a plurality of axiallyoriented, separate fingers, each of the fingers terminating distally atan inwardly extending tip.
 12. The apparatus of claim 11 wherein theaxle provides a distal reduced diameter portion, the fingers engagedtherewith.
 13. The apparatus of claim 10 wherein the axle provides atleast one flexible rubber O-ring, the at least one O-ring of a diameteras to create rotational resistance between the axle and the bushing. 14.The apparatus of claim 10 wherein the bushing provides a tapered surfacebetween the head and the external threads, the knob engaging the taperedsurface for locking the knob on the bushing.
 15. The apparatus of claim10 wherein the proximal head of the bushing provides radial stepsengagable with a peripheral edge of the paddle.
 16. The apparatus ofclaim 10 wherein the handle provides an axial slot.
 17. The apparatus ofclaim 10 wherein the knob provides a plurality of angularly spaced apartradial markers, the handle and the markers cooperating to identify theapproximate angular position of the paddle.
 18. The apparatus of claim14 wherein the knob provides a circular recess wherein with the knobengaged with the tapered surface of the bushing, an inner wall of thecircular recess flexes outwardly, thereby producing radial compressiveforces for securing the knob in place.